This NPR post reports that a small study of overweight adults found that avocado consumption can lead to a decrease in LDL cholesterol levels. We love that it confronts the lead researcher with a pointed question about the funding source for the study — something that a competing story based on a press release did not have or take the opportunity to do. But the story doesn’t explain whether the reductions in LDL cholesterol reported by the study are meaningful; why people should care about LDL cholesterol; how (or whether) this research fits into the existing body of work on avocados, diet and cholesterol; or how this decrease in LDL cholesterol compares to any other steps that can be taken to reduce LDL cholesterol levels.
Dietary changes to improve health outcomes (particularly important and common causes of death such as cardiovascular disease) are appealing because many people wish to avoid taking medications. New cholesterol guidelines result in a great number of people being recommended to take medications called statins, and after they start these medications, physicians no longer monitor their cholesterol profile. People wishing to avoid starting a statin may want to trial dietary changes including adjusting their intake of healthy fats.
Avocados are relatively expensive — a fact pointed out by several competing stories that covered this study, but not this story. Eating one per day regularly could cost in the ballpark of $30 per month, which may be out of reach for some people.
The story does compare the reduction of LDL cholesterol in study participants who ate avocado to reductions in LDL among study participants who did not. However, it is not clear if the differences are significant relative to the overall amount of LDL cholesterol found in blood — and the story never explains how LDL cholesterol is linked to human health. It would have been nice if the story had explained why people should care about their LDL cholesterol or why it is termed the “bad” cholesterol. Comparing the reductions seen with a common dose of Lipitor (atorvastatin), or explaining how the changes would affect one’s overall cardiovascular risk, would be helpful for readers.
The story says that eating avocados is linked to decreases in LDL cholesterol levels, but also clearly notes that eating avocados in conjunction with tortilla chips (as guacamole lovers are wont to do) would lead to a significant increase in calorie consumption.
The story doesn’t do quite enough to communicate the many limitations of this study. For example, one of the researchers notes in a related news release that “This was a controlled feeding study, but that is not the real world — so it is more of a proof-of-concept investigation,” but that sentiment was not made clear in the story. In addition, there was no discussion of the fact that the primary outcome — LDL cholesterol — is an intermediate marker of heart disease risk and only one of many different factors that affects risk. Thus, the findings are not as strong as those of some other studies that assessed the number of heart attacks and strokes that occurred after dietary changes.
No disease mongering here. While LDL is termed the “bad cholesterol” without explanation, the story also doesn’t equate high LDL cholesterol levels to disease or mortality.
The story relies entirely on one source, who was an author of the study. It would have been good to get additional input from other experts in the field. However, the story not only makes clear that the study was partially funded by an avocado industry organization, but discusses the issue at length.
The story does not compare the decrease in LDL levels found in this study to the effectiveness of other techniques that can lower LDL cholesterol, such as drug therapy, other changes in diet, weight loss, or increased exercise.
Avocados are widely available, so we won’t ding the story for not discussing availability. As with the competing stories, we would have liked to have seen some acknowledgment that there are areas where avocados may be more difficult to find.
A great deal of research has been done related to avocado consumption and cholesterol levels. The story doesn’t explain how this study either fits into the existing research on avocados and LDL cholesterol levels in humans or how it is different from previous studies on cholesterol and avocado consumption.
It was clear, based on multiple quotes in the story, that the reporter spoke at length to a researcher involved with the study, rather than relying solely on the news release.